The Basilica of St. Mary Formosa dates back to the 6th century. It is an exceptionally important Early Christian monument. Unfortunately, only the south chapel, shaped as a Greek cross, has been preserved.
Located in the south of the old town core, St. Mary Formosa is one of the most significant Early Christian monuments of the Byzantine art and architecture in Istria and Croatia. It was commissioned by Archbishop Maximianus of Ravenna from the vicinity of Rovinj, who also had San Vitale and San Appolinare in Classe erected, both in Ravenna.
The magnificent three-nave basilica was divided into three naves by columns, which interior rhythm was repeated on its exterior perimetral walls, the window division and blind arch lesenes. The sanctuary was completed by three polygonal arches and two side chapels next to it. Only the south chapel has been fully preserved until today, while the major part of the northern one was built into the neighbouring residential buildings.
The basilica's northern wall is today visible only as a fence surrounding the neighbouring garden. The chapel is designed as a Greek cross, one of which arms ends in a semi-circular axis, while its central part, the point where the two arms cross, is higher than the others. The sanctuary is covered by the quadro-pitched roof, while the remaining part of the structure has dual-pitched roofs. The exterior is simple, decorated by shallow lesenes, blind arches and semi-circular windows. It got ruined, especially during the 1242 fire at the time of the Venetian conquest of Pula. A large portion of its inventory was shipped to Venice, where it was used in building the St. Mark's Library or Sale delle quattro porte of the Doge's Palace.
In the late 16th century, the basilica was already in ruins.References:
The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.